In a manufacturing process of a semiconductor device, an etching target layer is etched by using a mask in order to form a required shape, such as a groove or a hole, on the etching target layer. When etching the etching target layer, a resist mask has been conventionally utilized. Since, however, the resist mask has low resistance against an etchant gas for the etching target layer or plasma of the etchant gas, a pattern of the resist mask may not be maintained until the etching of the etching target layer is completed.
For this reason, there has been employed a method of etching the target layer by using a hard mask which is formed by transcribing the pattern of the resist mask onto a hard mask layer through an etching process. In this method, however, the resist mask is still exposed to an etchant gas for the hard mask layer or plasma of the etchant gas when the hard mask is formed. Thus, the resist mask needs to have resistance against the etchant gas for the hard mask layer or the plasma of the etchant gas. That is, the resist mask is required to have etching resistance.
Conventionally used to improve the etching resistance of the resist mask is a curing process of hardening the resist mask by exposing the resist mask to hydrogen active species before etching the hard mask. Such a curing process is described in Patent Document 1.
Patent Document 1: Japanese Patent Laid-open Publication No. 2007-189153